The present invention concerns an oscillator generating a wave composed of a frequency on the order of terahertz from a stabilised beat of two optical waves generated by a dual-frequency optical source.
Generating and controlling terahertz (THz) waves is a field that at the present time is experiencing a regain in interest because of the progress in microelectronics and optics.
THz waves cover the electromagnetic spectrum lying between microwaves and the far infrared.
The applications sought are for example imaging, spectroscopy, the detection of chemical and biological species and the physics of phonon material and phonon light interactions.
Various techniques are currently used for generating THz waves.
The most widespread is based on the use of an impulse femtosecond laser associated with an antenna based on semiconductors wherein the life of the electrons is on the order of picosecond or on the use of an optical rectification crystal. The wave thus generated is spread over a spectral width that may be as much as a few THz. This technique does not make it possible to obtain a THz wave of high spectral purity.
Other techniques use techniques of multiple multiplications of a microwave frequency to reach a THz wave. These techniques are relatively complicated to implement.